The distribution and fluctuation of particle concentration in a supercritical water fluidized bed (SCWFB) are studied using a specially-designed capacitance probe measurement system. The measurement error of capacitance probe system is 2.48%. Results show that the particle concentration at the axial line fluctuates largely with time and the fluctuation is weakened when increasing the distance from axial line or decreasing particle diameter. At /=1.5, the largest difference between particle concentrations is 0.026, 0.04, 0.082 when the particles with a diameter of 0.124 mm, 0.198 mm, 0.235 mm are used, indicating a larger non-uniformity of larger particles. The probability density of local particle concentration mainly follows a unimodal distribution with the peak at right side. The main frequency of SCWFB ranges from 1.39 Hz to 2.73 Hz in this experiment and the main frequency decreases when larger particles are used.

中文翻译：

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超临界水流化床中颗粒的流化行为：区域相关分析

使用专门设计的电容探针测量系统研究了超临界水流化床（SCWFB）中颗粒浓度的分布和波动。电容探头系统的测量误差为2.48%。结果表明，轴线处颗粒浓度随时间波动较大，且随着距轴线距离的增加或粒径的减小，波动减弱。当/=1.5时，当使用直径为0.124mm、0.198mm、0.235mm的颗粒时，颗粒浓度之间的最大差异为0.026、0.04、0.082，表明较大颗粒的不均匀性较大。局部颗粒浓度的概率密度主要服从单峰分布，峰值在右侧。本实验中SCWFB的主频率范围为1.39 Hz至2.73 Hz，当使用较大颗粒时，主频率会降低。